Ground crews at the Guiana Space Center in South America have spent the last few months preparing the BepiColombo spacecraft, a tandem mission with European and Japanese science orbiters bound for Mercury, for launch aboard an Ariane 5 rocket.

Liftoff is scheduled for 0145 GMT on Oct. 20 (9:45 p.m. EDT on Oct. 19) from Kourou, French Guiana.

Workers at the spaceport in French Guiana have spent the last few months readying the BepiColombo spacecraft for launch. Key steps included filling of the spacecraft with propellant, and stacking the major parts of the vehicle together for the cruise to the solar system’s innermost planet.

This illustration shows the major components of the BepiColombo mission. At top is the Japanese Mercury Magnetospheric Orbiter. Below that is the spacecraft’s sunshield, which will cover the Japanese orbiter during the interplanetary cruise. Third from top is the European Mercury Planetary Orbiter, and at bottom is the European-built Mercury Transfer Module. Credit: ESA/ATG medialab

BepiColombo’s European-built Mercury Planetary Orbiter carries 11 instruments, a suite comprising a high-resolution mapping camera, a laser altimeter, an accelerometer, and a set of spectrometers on a downward-facing science deck that will remain pointed toward the planet throughout each orbit.

The spacecraft also includes the Mercury Transfer Module, a section with four steerable plasma engines and solar arrays designed to steer BepiColombo through the inner solar system through a series of gravity assist encounters with Earth, Venus and Mercury before finally arriving in orbit around the innermost planet in December 2025.

The BepiColombo modules will separate after arriving at Mercury, with the European and Japanese orbiters heading to different orbits. The Mercury Transfer Module will be jettisoned along with a sunshield that will keep the Japanese part of BepiColombo at the right temperature during the interplanetary transit from Earth to Mercury.

BepiColombo will become the second mission to orbit Mercury after NASA’s MESSENGER spacecraft, which explored the planet from 2011 through 2015.

The photos below show the BepiColombo spacecraft’s launch preparations in French Guiana after a series of Antonov cargo flights delivered the major pieces of the mission to the launch base from Europe.